I. Field of the Invention
The present invention relates generally to authentication using audio tones.
II. Background of the Invention
As Internet use has grown, many types of convenient electronic commerce have been made possible, such as, for example, buying goods and services online, banking online, and using automatic teller machines (ATM) that are linked to remote banks. But the very convenience of electronic commerce has made it easier for thieves to steal valuable information and/or to pose as someone they are not to purchase goods, withdraw money from bank accounts, and so on.
Accordingly, affording security in electronic transactions is crucial. To this end, many electronic transactions are encrypted, to conceal private information being exchanged. But encryption is only one aspect of security, since it only provides confidentiality. Encryption does not authenticate the parties involved or ensure the integrity/authenticity of the information being exchanged.
With this in mind, it readily may be appreciated that authentication is an important aspect of security. In terms of electronic commerce, the person seeking authentication does so through a computer interface. Consequently, it normally is not feasible to resort to checking a biological feature of the person (appearance, handwritten signature, fingerprint, and so on) to verify that the person is who he says he is, absent the widespread installation of an infrastructure of bio-sensing computer accessories.
This leaves two authentication factors available, namely, authenticating a person based on something the person has, such as a credit card or key fob, or based on something the person knows, such as a password or personal identification number (PIN). For some particularly sensitive applications such as ATM money withdrawals, both factors might be desirable.
The above-identified patent applications disclose hand-held sonic-based “tokens” that a person can manipulate to transmit an acoustic signal to a device, referred to as an “authenticator” or “verifier”, to authenticate the person based on the signal. As recognized in those applications, the advantage of sonic-based tokens is that a large installed infrastructure already exists to receive and transmit sound and electronic signals derived from sound. Specifically, the global telephone system exists to transmit data representative of acoustic information, and apart from telephones many computing devices that are now linked by this same system (as embodied in the Internet) have microphones and speakers (or can easily be modified to have them).
In the above-disclosed systems, a user can manipulate a token to send an acoustic signal to a verifier, with the acoustic signal representing a digital signature generated by using a private key known only to the user's token. The verifier receives the signal, converts it to electrical signals, and then uses a public key associated with the private key to verify the signature. Use of public key-private key principles facilitates robustness, in that a single token can be used for multiple purposes, such as for building access, vehicle access, ATM access, and so on, without the possibility that, for example, an unscrupulous security guard having access to a list of tokens authorized for building access could gain entrance to a vehicle or bank account that grants authorization to a token that happens to be on the building access list. Without the private key provided by the token, authorization cannot be granted by a verifier.
As recognized herein, the verifier can be controlled by a central computer that contains an access list used to verify a user's identity, based on the sonic signal received from a token. An example of such a verifier might be a building entrance verifier that allows entry into one or more buildings in a complex of buildings. To add or delete users from the access list, one need simply to modify the centrally-located list.
As also recognized herein, however, for certain other applications such as vehicle entry or home entry, verification is done at the location of the verifier, e.g., at the car or home. In these applications, adding or deleting a user from an access list can be more of a problem, because the verifier might not include a data entry device. Moreover, the present invention further recognizes that while it is desirable to enable a single token to be used to gain access to multiple verifiers, two closely located verifiers might receive the sonic activation signal and both grant access, when the user desires only access to one. For example, if a user has two vehicles parked in a driveway, both of which grant access based on a sonic token, it is desirable that the user be able to gain access to one of the vehicles without also unlocking the other vehicle, the front door of the house, etc. Having recognized these considerations, the invention described below is provided.